EP3607352A1

EP3607352A1 - Device for acquiring data on a target, platform and method therefor

Info

Publication number: EP3607352A1
Application number: EP18713996.9A
Authority: EP
Inventors: Philippe Riviere
Original assignee: Thales SA
Current assignee: Thales SA
Priority date: 2017-04-05
Filing date: 2018-04-04
Publication date: 2020-02-12
Anticipated expiration: 2038-04-04
Also published as: WO2018185178A1; IL269783A; IL269783B1; EP3607352B1; FR3065082B1; US11448761B2; IL269783B2; DK3607352T3; US20200191923A1; FR3065082A1

Abstract

The invention relates to a device for acquiring data (14) on a target (12), said device having an active imaging channel (16) comprising: - a laser source (22) transmitting laser beams (F1, ..., FN) having the same angle of divergence and a direction of propagation, the propagation directions all belonging to the same plane and being angularly spaced at the same spacing angle equal to M times the angle of divergence, - a unit (24) for deflection of the laser beams (F1, ..., FN) according to M positions, the deflection unit (24) being able to deflect the laser beams (F1, ..., FN) in the plane of the divergence angle, and the plurality of positions defining, in the plane, for each laser beam (F1, ..., FN), a continuous angular sector for transmitting the laser beam (F1, ..., FN), and - a detector (28) comprising a plurality of receivers (44_1, ..., 44_N) specific to a laser beam (F1, ..., FN).

Description

Device for acquiring data on a target, platform and associated method

The present invention relates to a device for acquiring data on a target. The present invention also relates to a platform comprising such a device and to a method for acquiring data on a target.

The invention lies in the field of target tracking, a field in which the operators wish to obtain a good accuracy on the distance of the target with a rate of refreshing the information on the high distance. The requirement of precision concerns relatively distant targets, including several kilometers.

For this, there are target tracking methods called "flash" type process.

In such processes, a laser light flash is sent to the target and its environment and received by a detector to obtain the position of the target.

However, the distance accuracy of such a technique is not sufficient.

There is a need for a data acquisition device on a target providing better distance accuracy with a high distance information refresh rate.

For this purpose, the present description describes a device for acquiring data on a target, the device comprising an active imaging channel of a target comprising a transmission part comprising a laser source capable of emitting a plurality of laser beams. each laser beam having an angle of divergence and a direction of propagation, the divergence angles having the same value, the propagation directions all belonging to the same plane and being angularly spaced in the plane of the nearest direction of propagation at the same spacing angle, the ratio between the spacing angle and the value of the divergence angles being equal to an integer strictly greater than 1 (hereinafter referred to as M), a deflection unit of the laser beams in a plurality of positions, the number of positions being equal to the integer (M), the deflection unit being adapted to deflect the laser beams in the plane a deflection angle equal to the value of the divergence angle, the plurality of positions defining in the plane, for each laser beam, a continuous transmitting angular sector specific to the laser beam considered. The active imaging channel comprises a reception part comprising a detector comprising a plurality of receivers, each receiver being specific to a laser beam, each receiver being arranged to receive the specific laser beam reflected by the target in each of the beam positions. specific laser and to obtain reception information from the specific laser beam, a calculator adapted to deduce the position of the target from the reception information.

According to particular embodiments, the data acquisition device comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:

each receiver comprises an input face having an angular extension in the plane whose value is equal to the value of the spacing angle.

each receiver comprises an input face having a center, the centers of the receivers being distributed along a first line and a second line, the second line being parallel to the first line and being distinct from the first line, the input face a receiver whose center is part of the first line being in contact with the input face of a receiver whose center is part of the second line.

each laser beam has a wavelength, the laser source being able to emit the laser beam in two distinct wavelengths.

the calculator is also suitable for deriving reflectivity information from the target from the reception information.

- The device further comprises a passive imaging channel of a target to obtain images of the target, the calculator deducing the position of the target also from the images of the target.

the laser source comprises a laser capable of generating laser light comprising the laser beams and optical fibers capable of propagating laser light, each optical fiber being specific to a laser beam and being equipped with a focusing collimator; laser beam shape.

each receiver is a fiber-optic photodiode.

The present description also relates to a platform comprising a device for acquiring data on a target as described above.

The present disclosure also relates to a method for acquiring data on a target by a data acquisition device comprising a computer and an active imaging channel of a target comprising a laser source, a deflection unit and a detector. the method comprising at least the step of emitting a plurality of laser beams by the laser source capable of emitting a plurality of laser beams, each laser beam having a divergence angle and a direction of propagation, the divergence angles having the same value, the propagation directions all belonging to the same plane and being spaced, angularly in the plane, from the direction of propagation closest to the same spacing angle, the ratio between the spacing angle and the value of the angles of divergence being equal to an integer strictly greater than 1 (M), of deflection of the laser beams in the plane of a deflection angle equal to the value of the angle of divergence by a deflection unit of the laser beams, the deflection step being implemented several times, to obtain an integer number of positions (M) defining in the plane, for each laser beam, a specific continuous emission angular sector to the laser beam considered, receiving the laser beams in each of the positions by a detector comprising a plurality of receivers, each receiver being specific to a laser beam, each receiver being arranged to receive the specific laser beam reflected by the target in each of the positions of the specific laser beam and to obtain specific laser beam receiving information, and calculator deduction of the position of the target from the reception information.

Other features and advantages of the invention will appear on reading the following description of embodiments of the invention, given by way of example only, and with reference to the drawings which are:

FIG. 1, a schematic view of a platform and a target, the platform being provided with an example of a data acquisition device,

FIG. 2, a schematic view of the data acquisition device and the target comprising a laser source capable of emitting a plurality of laser beams, a device for deflecting laser beams, receivers, a calculator and passive imaging,

FIG. 3, a schematic view of the laser source of the data acquisition device,

FIG. 4, a view illustrating the path of the laser beams passing through the afocal and the elevation deflection unit,

FIG. 5, a schematic view of the device for deflecting the laser beams in the plane,

FIG. 6, a schematic view of a laser beam,

FIG. 7, a schematic representation of the arrangement of the laser beams,

FIG. 8, a schematic view of a receiver, and

- Figure 9, a schematic front view of the plurality of receivers.

A platform 10 and a target 12 are shown in FIG.

In the example of Figure 1, the platform 10 is a land vehicle.

Alternatively, the platform 10 is a naval platform. In each case, a reference direction Dref corresponding to the direction passing through the data acquisition device 14 and pointing towards the target 12 is defined.

The plane perpendicular to the reference direction Dref corresponds to a vertical plane noted PV in the following.

In contrast, a plane perpendicular to a vertical plane PV is a horizontal plane PH.

It is also defined a direction of sight for a point of the target 12, the aiming direction connecting a target point 12 to the data acquisition device 14.

The angle between the sighting direction and the reference direction Dref in a horizontal plane PH is called azimuth.

The angle between the sighting direction and the horizontal plane PH is called the elevation angle.

By extension, the angular deflection of a laser beam in a horizontal plane PH is called azimuth deflection while the angular deflection of a laser beam in a vertical plane PV is called elevation deflection.

The target 12 is, according to the example shown, a person.

More generally, the target 12 is a target object for which a plurality of points of interest are defined.

Typically, for a person, the head or legs are points of interest.

The target 12 is at a relatively large distance from the platform 10.

For example, the distance between the target 12 and the platform 10 is of the order of 6 kilometers.

The platform 10 includes a data acquisition device 14 on the target 12.

The device 14 is thus able to acquire data relating to the target 12 or more exactly to the points of interest defined for the target 12.

In particular, the device 14 is able to define the position of the target 12.

The position of the target 12 is understood in the proposed context as the set of distances for each of the potential points of interest. By the expression "potential points of interest", it is understood a point in space for which it is likely that a point of interest of the target 12 is located.

The number of potential points of interest and the spatial distribution of the potential points of interest are chosen to allow identification of the target 12 given the uncertainty with which the target 12 is targeted. In our example, an image of 100 points in azimuth and 56 points in elevation is considered. These values allow, in our example, the identification of a person in his environment.

The device 14 is also suitable for obtaining other information on the target 12 such as the reflection properties of the points of interest of the target 12.

For example, the device 14 is able to obtain reflectivity information of the points of interest of the target 12.

The fact that a point of interest appears to be brighter than another point of interest is considered reflectivity information in this context.

The device 14 is also suitable for detecting the target 12 in a complex environment by post-processing or when the target 12 is partially masked.

The device 14 is further adapted to obtain such information at a rate greater than 30 Hz.

As can be seen in FIG. 2, the device 14 includes an active imaging channel 16, a passive imaging channel 17 and a computer 18.

The active imaging pathway 16 is an active imaging pathway of the target 12.

By the term "active", it is understood that the imaging path illuminates the target 12 by light emission and is able to obtain images of the target 12 by collection of the light reflected by the target 12 or the environment of the target. the target 12.

The active imaging path 16 includes a transmitting portion 19 and a receiving portion 20.

As can be seen in FIGS. 2 to 5, the transmission part 19 comprises a laser source 22, an opto-deflector unit 23 comprising an azimuth deflection unit 25 and an afocal 26 including an elevation deflection unit 24. FIG. 2 also illustrates the receiving portion 20 having a second azimuth deflection unit 27 and a detector 28.

The transmission part 19 is now described.

The laser source 22 is able to emit a plurality of laser beams.

The laser beams are marked by reference signs Fi where i is an index ranging from 1 to N, N being an integer identifying the number of laser beams.

N is an integer greater than or equal to 2.

Preferably, the number N is greater than or equal to 4.

According to the proposed example, the number N is equal to 8 as it appears in FIG.

In this example, the laser source 22 comprises a laser 29 and eight optical fibers 30_1 to 30_N. The laser 29 is adapted to generate laser light comprising the laser beams F1 to FN. The corresponding laser light forms a single beam denoted F in FIG.

The laser 29 is, for example, a fiber laser comprising a main fiber.

For example, the main fiber of the laser 29 is adapted to the wavelength of the laser. In the example, the fiber is silica.

The main fiber of the laser 29 supplying the beam F is separated into eight optical fibers 30_1 to 30_N as illustrated schematically in FIG. 3 with the element whose reference sign is 31.

Each optical fiber 30_i is able to propagate laser light. Each optical fiber 30_i is specific to a laser beam Fi.

In the proposed example, each optical fiber 30_i is equipped with a collimator 32_i laser beam shaping.

The laser source 22, that is to say the set of elements forming part of the laser source 22, is arranged so that the position of the laser beams F1 to FN is spatially specific.

Before describing the specific position of the laser beams F1 to FN, it is appropriate to describe with reference to the diagram of FIG. 6 generalities on the laser beams F1 to FN.

Each laser beam Fi has a wavelength denoted Ai.

In the example proposed, the wavelengths belong to the near infrared domain.

For example, it is assumed that each laser beam Fi is at a wavelength of 1.5 μηι.

Each laser beam Fi has a divergence angle θi and a propagation direction denoted DPi.

In fact, each laser beam Fi has a spatial distribution in the substantially Gaussian divergence 9i. The diameter of the bundle at the neck is indicated in Figure 6 by the reference sign Di.

In the example described, the angles of divergence Θ1 to ΘΝ of each laser beam F1 to FN all have the same value Θ.

In addition, as shown in FIG. 7, the propagation directions DP1 to DPN of each laser beam F1 to FN all belong to the same plane P.

In the case of Figure 2, the plane P is a vertical plane PV. The propagation directions DP1 to DPN are equi-angularly spaced in the plane P. This means that a propagation direction DP1 to DPN is spaced from the propagation direction DP1 to DPN closest to the same spacing angle aE .

In FIG. 7, the first direction of propagation DP1 is spaced from a spacing angle aE (in the direction of elevation) of the second direction of propagation DP2 while the third direction of propagation DP3 is spaced from an angle spacing aE (in the direction of elevation) of the second propagation direction DP2.

The ratio between the spacing angle aE and the value of the divergence angles Θ is equal to an integer M strictly greater than 1. This mathematically means that:

aE aE aE aE aE

Ή ^{~ '} θ2 ^{~''~ ~} θϊ ^{~ "' ~} ΘΝ ^{~ ~} θ ^{~ ~ Μ}

Preferably, the integer M is strictly greater than 4.

For example, in the embodiment described, the integer M is equal to 7. The laser source 22 is arranged so that the position of the laser beams F1 to FN is a position verifying the previous conditions.

In the example described, to obtain such a specific position, the optical fibers 30_i are single-mode to maintain the beam quality emitted by the laser 29.

The laser source 22 thus makes it possible to obtain a plurality of laser beams F1 to FN arranged in the specific position illustrated in FIG. 7.

The elevation deflection unit 24, the azimuth deflection unit 25 and the afocal 26 have the function of bringing the plurality of laser beams F1 to FN emitted towards the target in a positionally controlled manner.

The elevation deflection unit 24 of the F1 to FN laser beams is adapted to deflect the laser beams at a plurality of positions P1 to PM.

The number of positions P1 to PM is equal to the integer M.

The elevation deflection unit 24 is adapted to deflect the laser beams F1 to FN in the plane P by a deflection angle equal to the value of the divergence angle Θ.

The elevation deflection unit 24 is also a jump deflection unit. More precisely, assuming that the position P1 is an extremal reference position, the elevation deflection unit 24 is adapted to deflect each laser beam F1 to FN by a deflection angle Θ from the first position to put each of these laser beams F1 to FN in the second position P2. The deflection unit 24 is also adapted to deflect each laser beam F1 to FN by a deflection angle 2 ^* 9 from the first position to put each of these laser beams F1 to FN in the third position P3. The deflection unit 24 is also adapted to deflect each laser beam F1 to FN with a deflection angle (Ν-1) ^* θ from the first position P1 to put each of these laser beams F1 to FN in the last position PN .

More generally, the elevation deflection unit 24 is also adapted to deflect each laser beam F1 to FN by a deflection angle (i-1) ^* θ from the first position to put each of these laser beams F1 to FN in the i-th position Pi.

As a result, the plurality of positions P1 to PM defines in the plane P, for each laser beam F1 to FN, an angular sector S1 to SN continuous emission specific to the laser beam F1 to FN considered.

The azimuth deflection unit 25 is a deflection unit of the F1 to FN laser beams in azimuth.

The azimuth deflection unit 25 is, according to the example described, a mirror.

As can be seen in FIG. 4, the afocal 26 has a magnification G.

The afocal 26 comprises, according to the example of FIG. 5, a first lens 36 carried by the elevation deflection unit 24 and a second lens 38 spaced a distance equal to the sum of the first focal length f1 of the first lens 36 and the second focal length f2 of the second lens 38.

The magnification G is equal to the ratio of the first focal length f38 to the second focal length f36.

The magnification G is, for example, greater than 10.

A laser beam Fi then presents in the object space (at the exit of the afocal 26) an angular divergence equal to Θ / G.

Typically, the divergence of each laser beam Fi is between 50 microradians (rad) and 100 micron. For example, the angular extent is equal to 70 μταά.

It should be noted that in the example, the optical fibers 30_i are arranged in a circular arc with a suitable angular spacing, the angular spacing is equal to G times the spacing angle aE.

In addition, as shown schematically in FIG. 5, the deflection unit 24 is able to cause displacement of the first lens 36.

The transmission part 19 is thus able to illuminate potential points of interest of the target 12 with a scan in the azimuth and elevation directions using the eight laser beams F1 to FN.

The laser beams are then reflected by the potential points of interest of the target 12 to the receiving portion 20 which receives the reflected laser beams.

As previously explained, the receiving part 20 comprises a second azimuth deflection unit 27 and a detector 28. The second azimuth deflection unit 27 comprises a collection lens 40 and a deflection mirror 42.

The collection lens 40 collects all of the laser beams reflected towards the deflection mirror 42.

The deflection mirror 42 is an azimuth deflection mirror.

The deflection mirror 42 and the azimuth deflection unit 25 are synchronized.

The detector 28 comprises a plurality of receivers 44 1 to 44 N.

Each receiver 44_i is specific to a laser beam Fi.

This implies that the detector 28 comprises N receivers 44 1, ..., 44 N.

Each receiver 44_i is arranged to receive the specific laser beam Fi reflected by the target 12 in each of the positions P1 to PM of the specific laser beam Fi.

Each receiver 44_i makes it possible to obtain information of reception of the specific laser beam Fi.

The reception information comprises in particular the instant of reception of the laser beam Fi or the amplitude of the reflected laser beam Fi.

According to the example described, each receiver 44_i is a fiber-optic diode visible more specifically in FIG.

Each receiver 44_i comprises an optical fiber 46_i and a photodiode 47_i.

Each optical fiber 46_i makes it possible to define an input face Fei having an angular extension.

The angular extension of each receiver 44_i has a value equal to the value of the spacing angle aE.

Each input face Fei having a center Oi.

Each optical fiber 46_i of each receiver 44_i is multimode.

Each optical fiber 46_i of each receiver 44_i comprises a core 48_i and a sheath 49_i.

The core 48_i is, for example, made of silica.

The diameter of the core 48_i has a dimension of the order of 100 μηι.

The diameter of the sheath 49_i has a dimension of between 125 μηι and 150 μπι.

The photodiode 47_i is, for example, an avalanche photodiode.

As seen in FIG. 9, the receivers 44_i are arranged in a staggered configuration.

The centers Oi of the receivers 44_i are distributed along a first line 50 and a second line 52. The second line 52 is parallel to the first line 50. The second line 52 is distinct from the first line 50.

The input face Fei of a receiver 44_i whose center Oi is part of the first line 50 is in contact with the input face FEi of a receiver 44_i whose center Oi is part of the second line 52.

More precisely, in FIG. 9, the input faces FE1, FE2, FE3 and FE4 of four receivers 44 1, 44 2, 44 3 and 44 4 are represented. The centers 01 and 03 of the first and third receivers 44 1 and 44 3 are aligned along the first line 50 while the centers 02 and 04 of the second and fourth receivers 44 2 and 44 4 are aligned along the second line 52.

In addition, the sheath 49 2 of the second receiver 44 2 is in contact on the one hand with the sheath 49 1 of the first receiver 44 1 and on the other hand with the sheath 49 3 of the third receiver 44 3 while the sheath 49 3 the third receiver 44 3 is in contact on the one hand with the sheath 49 2 of the second receiver 44 2 and on the other hand with the sheath 49 4 of the fourth receiver 44 4.

The receiving part 20 is thus able to obtain laser beam receiving information reflected from the target 12.

Passive imaging path 17 is a passive imaging path of target 12, i.e., an imaging path capable of obtaining images of target 12.

By the term "passive", it is understood that the imaging pathway does not illuminate the target 12 by light emission and is able to obtain images of the target 12 by collection of thermal radiation from the target 12 or the environment of the target 12.

The passive imaging channel 17 is, according to the example described, a camera.

The camera is, for example, sensitive to photons in the 3 micrometer (μηι) band at 5 μηι.

The computer 18 is adapted to derive the position of the target 12 from the reception information.

The computer 18 is also adapted to derive reflectivity information from the target 12 from the reception information.

The computer 18 is also able to deduce the position of the target 12 also from the images of the target 12 obtained using the passive imaging path 17.

The operation of the device 14 is now described with reference to FIGS. 10 to 12 and to an exemplary implementation of a method for acquiring data on the target 12. The acquisition method comprises a plurality of steps implemented several times, the plurality of steps comprising a transmission step, a deflection step, a reception step and a deduction step.

During the transmission step, the laser source 22 emits the plurality of laser beams F1 to FN in one of the specific positions described with reference to FIG.

During the reception step, the laser beams F1 to FN reflected by the target 12 are received by the specific receiver 44_i. Each receiver 44_i then behaves like a flow collector.

This makes it possible to obtain information on the reception of the specific laser beam F1 to FN.

During the deflection step, the deflection unit 24 deflects the laser beams F1 to FN in the plane P by a deflection angle equal to the value of the divergence angle Θ to go from one position to one. other position.

During the deduction step, the computer 18 derives the position of the target 12 from the reception information by a flight time technique. More specifically, the time elapsed between the emission of a laser beam and the reception of the reflected laser beam is proportional to the distance between the target 12 and the data acquisition device 14.

By way of example and with reference to FIGS. 10 to 12, it is assumed that the scanning of the potential points of interest of the target 12 is implemented by constant azimuth lines, the azimuth being modified using of the azimuth deflection unit 25, for each azimuth line, the elevation deflection unit 24 deflects the laser beams F1 to FN at one of the positions P1 to PM.

For simplicity, a case with three beams has been illustrated for Figures 10 to 12 for a given azimuth.

In FIG. 10, each of the three beams F1, F2 and F3 is in the first position P1; in FIG. 11, each of the three beams F1, F2 and F3 is in the second position P2 and in FIG. 12, each of the three beams F1, F2 and F3 is in the second position P3. The transition from one position to another is done using the deflection unit 24.

It appears that, for the first beam F1, the passage in the three positions P1, P2 and P3 makes it possible to scan the entire first angular sector S1 in elevation. The same remark applies for the second beam F2 vis-à-vis the second angular sector S2 and the third beam F3 vis-à-vis the third angular sector S3.

The three angular sectors S1, S2 and S3 being continuous in elevation, a relatively fast elevation sweep is thus achieved. The expression "fast" is to be understood by comparison with a device 14 which would perform a point-by-point scan. In the illustrated case, 9 deflections in elevation should be made while 3 are sufficient in the case presented. This represents a gain of a factor M which is equal to 3 in the proposed case. The advantage is all the more marked as the number of lines in elevation is large.

As illustrated by the arrows 60 on the target 12 in FIG. 2, the scanning is carried out by constant elevation azimuth lines, the elevation being modified by means of the elevation deflection unit 24 as soon as a line in azimuth has been completed.

Alternatively, the scanning could be performed using constant azimuth elevation columns, the azimuth being changed using an azimuth deflection unit as soon as an elevation column has been completed.

In such a variant, the gain in number of deflections explained above is also valid in this case.

The gain in number of deflections makes it possible to obtain position information of the target 12 and reflectance of the target 12 to identify the target 12 at a higher rate (M times faster) while obtaining a centimeter measurement of the distance target 12 - platform 10 for each point of interest of the target 12.

Otherwise formulated, the device 14 makes it possible to obtain a multiplexing of the transmission and reception channels making it possible to obtain a high active imaging rate.

The range of the device 14 is large, several kilometers. The device 14 also makes it possible to cover a relatively large field. For example, using the number of points defined below, the device 14 can cover 4 by 7 milliradians approximately.

By way of illustration, for such a field, assuming that the number of potential points of interest is 5600 with M = 7 and N = 8, the device 14 is able to obtain a maximum refresh rate of the information from 143 Hz to 1500 meters or from 35 Hz to 6000 meters.

The data acquisition device 14 thus has a better accuracy in distance with a refresh rate of the information on the high distance.

In a particular example, the device 14 is used to obtain a centimeter accuracy of the distance of a target located off axis of the target direction to allow to timed the flight time of a munition.

Other embodiments are possible for the device 14.

According to another embodiment, the laser source 29 comprises two lasers emitting in two different wavelengths. F1 to FN laser beams can in this case be connected to one or the other laser via an optical switch. The photodiodes of reception are, in this case, compatible with the wavelengths envisaged.

For example, the first laser is at a first wavelength of 1.06 μηι while the second laser is at a second wavelength of 1.55 μηι. The receiving photodiodes are InGaAs. This allows the user of the device 14 to benefit from a choice in the operating wavelength of the transmission part 19.

The present invention also covers all technically possible combinations of the embodiments which have just been presented in the foregoing description.

Claims

1 .- A device (14) for acquiring data on a target (12), the device (14) comprising:

an active imaging channel (16) comprising:

an emission part (19) comprising:

a laser source (22) able to emit a plurality of laser beams (F1, FN), each laser beam (F1, FN) having a divergence angle (Θ1, ..., ΘΝ) and a propagation direction (DP1 , DPN), the angles of divergence (Θ1, ..., ΘΝ) having the same value (Θ), the directions of propagation (DP1, DPN) all belonging to the same plane (P) and being spaced angularly in the plane (P), the direction of propagation (DP1, DPN) closest to the same spacing angle (aE), the ratio between the spacing angle (aE) and the value of the angles of divergence ( Θ) being equal to an integer (M) strictly greater than 1,

a deflection unit (24) of the laser beams (F1, FN) according to a plurality of positions (P1, PM), the number of positions (P1, PM) being equal to the integer number (M), the deflection unit (24) being adapted to deflect the laser beams (F1, FN) in the plane (P) by a deflection angle equal to the value of the divergence angle (Θ), the plurality of positions (P1, PM) defining in the plane (P), for each laser beam (F1, FN), a continuous angular sector (S1, SN) of emission specific to the laser beam (F1,

FN) considered, and

a reception part (20) comprising:

a detector (28) comprising a plurality of receivers (44 1, ..., 44 N), each receiver (44 1, ..., 44 N) being specific to a laser beam (F1, FN), each receiver (44 1, ..., 44 N) being arranged to receive the specific laser beam (F1, FN) reflected by the target (12) in each of the positions (P1, PM) of the specific laser beam (F1, FN) and to obtain specific laser beam receiving information (F1, FN), - a computer (18) adapted to derive the position of the target from the reception information.

2. - Device according to claim 1, wherein each receiver (44 1,

44 N) has an input face (FE1, FEN) having an angular extension in the plane (P) whose value is equal to the value of the spacing angle (aE).

3. - Device according to claim 1 or 2, wherein each receiver (44 1, ..., 44 N) comprises an input face (FE1, FEN) having a center (01, ON), the centers (01 , ON) receivers (44 1, ..., 44 N) being distributed along a first line (50) and a second line (52), the second line (52) being parallel to the first line (50) and being distinct from the first line (50), the input face (FE1,

FEN) of a receiver (44 1, ..., 44 N) whose center (01, ON) is part of the first line (50) being in contact with the input face (FE1, FEN) of a receiver (44 1, ..., 44 N) whose center (01, ON) is part of the second line (52). 4.- Device according to any one of claims 1 to 3, wherein each laser beam (F1, FN) has a wavelength, the laser source (28) being adapted to emit the laser beam (F1, FN) in different wavelengths.

5. - Device according to any one of claims 1 to 4, wherein the computer (18) is also adapted to deduce reflectivity information from the target

(12) from the reception information.

6. - Device according to any one of claims 1 to 5, wherein the device (14) further comprises a passive imaging path (17) of a target (12) to obtain images of the target (12), the calculator (18) deducing the position of the target (12) also from the images of the target (12).

7. - Device according to any one of claims 1 to 6, wherein the laser source (22) comprises a laser (29) capable of generating laser light comprising the laser beams (F1, FN) and optical fibers ( 30_1, 30_N) adapted to propagate laser light, each optical fiber (30_1, 30_N) being specific to a laser beam (F1, FN) and being equipped with a collimator (32 1, ..., 32 N) laser beam shaping. 8.- Device according to any one of claims 1 to 7, wherein each receiver (44 1, ..., 44 N) is a fiber photodiode.

9. Platform (10) comprising a data acquisition device (14) on a target (12) according to any one of claims 1 to 8. 10.- Method of acquiring data on a target ( 12) by a data acquisition device (14) comprising a computer (18) and an active imaging channel (16) comprising a laser source (22), a deflection unit (24) and a detector (28) the process comprising at least the step of:

- emission of a plurality of laser beams by the laser source (22) able to emit a plurality of laser beams (F1, FN), each laser beam (F1,

FN) having a divergence angle (Θ1, ..., ΘΝ) and a propagation direction (DP1, DPN), the divergence angles (Θ1, ..., ΘΝ) having the same value (Θ), the directions propagation paths (DP1, DPN) all belonging to the same plane (P) and being spaced angularly in the plane (P) of the direction of propagation (DP1, DPN) closest to the same spacing angle ( aE), the ratio between the spacing angle (aE) and the value of the divergence angles (Θ) being equal to an integer (M) strictly greater than 1,

deflection of the laser beams (F1, FN) in the plane (P) by a deflection angle equal to the value of the divergence angle (Θ) by a deflection unit

(24) laser beams (F1, FN), the deflection step being implemented several times, to obtain an integer number (M) of positions (P1, PM) defining in the plane (P), for each beam laser (F1, FN), a continuous angular sector (S1, SN) of emission specific to the laser beam (F1, FN) considered,

- Receiving laser beams (F1, FN) in each of the positions (P1, PM) by detector (28) having a plurality of receivers (44 1, ..., 44 N), each receiver (44 1, ... , 44 N) being specific to a laser beam (F1, FN), each receiver (44 1, ..., 44 N) being arranged to receive the specific laser beam (F1, FN) reflected by the target (12) in each of the positions

(P1, PM) of the specific laser beam (F1, FN) and to obtain specific laser beam receiving information (F1, FN), and

- deduction by the computer (18) of the position of the target (12) from the reception information.